Improve biome blending in 3D (#1637)

* Only do 3D blur when necessary during biome blending. Do only 2D blur when possible

* Implement 2D blur using a summed-area table and fix bugs observed during testing

* Implement 3D blur using a summed-area table too

* Narrow the y interval on which biome blending must be done by querying the blocks to know if they use biome blending

* Group 3D blur computation for transition that are close to one another

* Expose control in UI for biome blending radius

* Clean up

* Rename useBiomeTint to isBiomeDependant. Make 2D biome benefit from tracking whether biome is used int the chunk or not

* Don't use title case for the biome blending checkbox.

* Fix bug where chunk on the edge of the selection when the chunk coordinate are negative had wildy wrong biome colors due to off by 1 error when testing if the chunk is loaded caused by int division rounding behavior

---------

Co-authored-by: Maik Marschner <[email protected]>

chunky/src/java/se/llbit/chunky/block/AbstractModelBlock.java

@@ -45,4 +45,9 @@ public BlockModel getModel() {
   public boolean intersect(Ray ray, Scene scene) {
     return model.intersect(ray, scene);
   }
+
+  @Override
+  public boolean isBiomeDependant() {
+    return super.isBiomeDependant() || model.isBiomeDependant();
+  }
 }

chunky/src/java/se/llbit/chunky/block/Block.java

@@ -146,4 +146,11 @@ public boolean isModifiedByBlockEntity() {
   public Tag getNewTagWithBlockEntity(Tag blockTag, CompoundTag entityTag) {
     return null;
   }
+
+  /**
+   * Does this block use biome tint for its rendering
+   */
+  public boolean isBiomeDependant() {
+    return isWaterFilled();
+  }
 }

chunky/src/java/se/llbit/chunky/block/legacy/blocks/LegacyFlowerPot.java

@@ -83,4 +83,9 @@ public Tag getNewTagWithBlockEntity(Tag blockTag, CompoundTag entityTag) {
 
     return tag; // keep empty
   }
+
+  @Override
+  public boolean isBiomeDependant() {
+    return true; // (in reality it is only used for fern)
+  }
 }

chunky/src/java/se/llbit/chunky/block/legacy/blocks/LegacyVine.java

@@ -27,4 +27,9 @@ public void finalizeBlock(FinalizationState state) {
     // otherwise just unwrap the block
     state.replaceCurrentBlock(tag);
   }
+
+  @Override
+  public boolean isBiomeDependant() {
+    return true;
+  }
 }

chunky/src/java/se/llbit/chunky/model/AABBModel.java

@@ -9,6 +9,7 @@
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 import java.util.Random;
 
 /**
@@ -181,4 +182,16 @@ private boolean intersectFace(Ray ray, Scene scene, Texture texture, UVMapping m
     }
     return false;
   }
+
+  @Override
+  public boolean isBiomeDependant() {
+    Tint[][] tints = getTints();
+    if(tints == null)
+      return false;
+
+    return Arrays.stream(tints)
+      .filter(Objects::nonNull)
+      .flatMap(Arrays::stream)
+      .anyMatch(Tint::isBiomeTint);
+  }
 }

chunky/src/java/se/llbit/chunky/model/BlockModel.java

@@ -18,4 +18,6 @@ public interface BlockModel {
   void sample(int face, Vector3 loc, Random rand);
 
   double faceSurfaceArea(int face);
+
+  boolean isBiomeDependant();
 }

chunky/src/java/se/llbit/chunky/model/QuadModel.java

@@ -28,6 +28,8 @@
 import se.llbit.math.Vector3;
 import se.llbit.math.Vector4;
 
+import java.util.Arrays;
+import java.util.Objects;
 import java.util.Random;
 
 /**
@@ -148,4 +150,14 @@ public boolean intersect(Ray ray, Scene scene) {
     }
     return hit;
   }
+
+  @Override
+  public boolean isBiomeDependant() {
+    Tint[] tints = getTints();
+    if(tints == null)
+      return false;
+
+    return Arrays.stream(tints)
+      .anyMatch(Tint::isBiomeTint);
+  }
 }

chunky/src/java/se/llbit/chunky/model/Tint.java

@@ -98,4 +98,8 @@ public void tint(Vector4 color, Ray ray, Scene scene) {
       color.z *= tintColor[2];
     }
   }
+
+  public boolean isBiomeTint() {
+    return type == TintType.BIOME_FOLIAGE || type == TintType.BIOME_GRASS || type == TintType.BIOME_WATER;
+  }
 }